Method and apparatus for making grommets



July 1o, 1956 H. J. HANSEN ETA; 2,753,678

METHOD AND lAPPARATUS FOR MAKING GROMMETS Filed Feb. 2, 1953 2SheeS-Sheet l lllllu July 10, 1956 H. J. HANSEN ETAL 2,753,678

METHOD AND APPARATUS FOR MAKING GROMMETS Filed Feb. 2, 1953 2sheets-sheet 2 FISE. il 7@ METHOD AND APPARATUS FOR MAKING GROMlVIETSHarry J. Hansen, Hamden, andy Arvin P. Wiedemann,

North Haven, Cnn., assigliors to United States SteelI Corporation, acorporation of New Jersey Application February 2, 1953, Serial No;334,694l 7 Claims. (Cl..5-2`1) used in forming a grommet, other wirestructures, such as` a single wire, rope or plastic mono-lament may alsobe used. For the. purposes of clarity and simplicity in describing thepresent invention, the element of which the grommet is formed willhereinafter be referredto as a strand. l

In a common grommet, they endporti'ons of :the single length of strandof which the grommet is made are straight, that is, free of any set orhelical formation, andforin the core and tuck of the grommet.Themicl-portion ofthe strand has a preformed helicalset and forms the`outer layers.

An object of our yinvention is to provide an apparatus o and method formaking a grommet from a single length of wire strand.

It is a further object of our invention to providefanV apparatus andmethod .formakinga grommet from a` single length of strand Vhaving avpreformed helically set mid-portion and straightend portions.

These and other objects will becomefmore apparent after referring to thefollowing specification adattached drawings, in which: p

Figure 1 is a side elevation of our invention;y

Figure 2 is an end elevationl of Figure 1;y p

Figure 3 is an enlarged .side elevation of a latchng mechanism;

Figure 4 is an end ,elevation of Figure 3; l

Figure 5 is a detail showing the upper half of a die block; n

Figure 6 is anl end elevation .of FigureS;

Figure 7 is a detail showing the l'o'wer half of a die block; n

Figure 8 i-s an end. elevationof` Figure 7'; and u Figure.9 is aviewshowing arrarrangement-ofthe straight and helical sections of astrandt Referring more particularly to the drawings, reference numeral 2indicates a base on which two pairs of grooved rollers 4 and 6 aremounted in bearings 8 and 10 respectively. An interconnecting driveshaft 12 connects and drives the rollers 4. The drive shaft is rotatedby means of a sprocket 14, which is rigidly mounted on the shaftintermediate its ends. A chain 16 connects the sprocket 14 with asprocket 18 which is mounted on the shaft 20 of a speed reducer 22. Thespeed reducer, in turn, is operatively connected with a variable speed,reversible motor 24.

Rotor plates or wheels 26 and 28 are rotatively mounted on the pairs ofrollers as best shown in Figure 1. A cradle or cage 30 is rotativelysupported between the plates 26 and 28 for holding a supply reel 32 uponwhich lCe may be coiled a wire strand S of predeterminedlength to beformed into a grommet.

The ends of the cradle 30 are rotatively supported in bearings 34 and 36in` plates 26 and 28,V respectively; by means of shafts 35-and 37 whichproject from the' .ends of the( cradle.- Shaft 377, which fits into the:bearing 36, is hollow. Each of the shafts 3 5 and 37 project outwardlybeyond the .plates a short distance and have outer- Inner flanges 411'and 43 are:

flanges 39 fittedy thereon. v fitted around each ofthe shafts 35 and37,respectively, inwardly of the plates 26 and 2S. y

The plates 26 and 28 may beconnected together for unitary rotation bymeans offtie bars 38 and nuts 40.

The two side members 42 of the cradle 30 vare pro= vided with matchingslots or notches `44 for supportingthe axial shaft 46 of the reel 32. AAn angular plate extension 48 may be provided o-n each ofthe sidemembers 42 adjacent and .below the slots 44`for pivotallymountinglatches 50. Latches 50 function to keep the shaft 4,6 in position whilethe machine is operating. Latch 50, is maintained inoperatingposition'by means of helical tension springs 52. A pair ofsmall rollers 54'may be provided in opposed position,y one on each side.of the side members 42, adjacent'each of theslots 44 to engage andsupportthe reel` shaft 46 and thus insure smooth rotation of the supplyreel 32 asstrand is withdrawn therefrom.I y j A brace 56 extends betweentheside members 42 intermediate the slots 44 and the plateZS. Acounterweight 5S is suspended from the brace 56 and another counterWeight 58 issuspended from the inner llange 41 for preventing rotationof thecradle 30 when platesA 2'6 andi-128i are rotated. A p A brake.mechanism 60 is provided. for applyingsuflicient restraint againstrotation of the supply reel.3 2so that the reel will .not rotate unlessthe strandk S is being pulled. The brake mechanism includes a .pairofbrake wheels 62 one of which is ltted on the supply reel shaft adjacenteach side of the reel. A brake' rope 64frictionally. engages asubstantial portion of the .gro'ov'ed periphery of each wheel. Each ofthe brake Vropes is anchored at one end to brackets 66'ailiXed toside'memf b'ers 42. Their other ends are adjustablyy attached to the`lower ends of vbrake levers 67 which are pivotally mounted on the sidemembers 42. The upper end of each lever isrv connected with an adjustingscrew 68 which,at its opposite end', threadingly engages a screw plate70 which is mounted on the brace 56. Each of the brake wheels is.rigidly connected with its respective sidelof the supply reel-by meansof integral pegs 72 .which Vproject from the yside ofy the.

brake wheels and iitint'osuitable holes in the sides of the' supply reelas best shown inv Figure 4. A

Die blocks 74 and. '74" are tted at a pointadjacent the periphery oftheplates 26- and 2K8 respectively. The

upper halves 76 and 76"- of each ofthe die blocks'A is.

removable for a'purposewhich will become apparent as thisdesc''ptionproceeds.. y p l l y In operation, apredetermined'flength of.strand...-liaving` straight' end portions" S1l and S3A and 'a preformedhelical'l mid-portion S2 is coiled about the supply reel 32, and thesupply reel is mounted in the cradle 30 as described above.

Figure 9 illustrates a preferred arrangement of the straight and helicalsections of the strand which is to be assembled into a grommet. SectionS1 is straight and is equal in length to the circumference of the nishedgrommet desired. This straight portion will form the core C of thegrommet. The length of the section S2 is equal to that of thecircumference multiplied by the number of times the strand is to bewrapped about itself, multiplied by the secant of the angle of lay ofthe strands with respect to an axis coincident with the core of the 3grommet. The number of times a strand is wrapped about itself in forminga grommet is usually -six but may be more or less than this number asdesired. The end portion S3 is a relatively short length of straightstrand which is tucked or rolled into the center of the grommet at itscompletion.

After the reel 32 bearing the coil of the strand S has been properlypositioned in the cradle 30, the strand is passed manually from the reelthrough the central opening of the shaft 37 outwardly of the plate 2Sand looped out and around the cradle as shown in Figure l, and thenpassed through the die block 74, then through the die block 74. A loopis then formed by seizing the lead end of the strand to the irst end Pof the helically preformed mid-portion S2. The loop thus formed is ofthe same circumferential dimension as and constitutes the core C of thegrommet to be made. After the loop has been thus formed, the motor 24 isactuated to rotate the plates 26 and 28 which causes the loop to bethrown as a hoop around the cradle and the plates. As the plates rotate,the loop is continuously pulled manually in an axial direction from theplate 26 to plate 28 through the dies whereby the strand issuing fromthe plate 28 is laid on the core in helical convolutions. This iscontinued until the desired number of layers of helical convolutionshave been laid about lthe core.

When the last end S3 of the strand emerges from the plate 28, the layersof helical convolutions are parted and a portion of the core adjacentthe last end S3 is cut out and the end S3 is inserted in its place.

On completion of the grommet as described, the remov able portions 76and 76' of the dies 74 and 74 are removed to permit removal of thegrommet from the machine.

Although we have shown and described but one embodiment of ourinvention, it will be apparent that other adaptations and modificationsmay be made without departing from the scope of the following claims.

We claim:

1. Apparatus for making grommets comprising a pair of wheelsrotativelydisposed coaxially and in spaced relation to each other, a pair ofsupporting rollers engaging the periphery of each wheel, a framevextending between and supported by said wheels for rotation withrespect thereto, means attached to said frame tending to hold the samestationary when the wheels are turned, and means carried by said framefor supporting a reel, one of said wheels having a central eye throughwhich strand coiled on said reel may be drawn off, said wheels havingsubstantially aligned openings adjacent their periphery to receive saidstrand.

2. Apparatus for making grommets comprising a pair of vertical Wheelsrotatively disposed coaxially and in spaced relation to each other, apair of spaced supporting rollers below said wheels engaging theperiphery thereof, a horizontal frame extending between and supported bysaid wheels for rotation with respect thereto, a weight supported bysaid frame below the axis thereof, said weight tending to hold saidframe stationary when vthe wheels are turned, means carried by saidframe for supporting a reel on a normally horizontal axis parallel tosaid wheels, one of said wheels having a central eye 'through whichstrand coiled on said reel may be drawn off, said wheels havingsubstantially aligned openings adjacent their periphery to receive saidstrand, and means connected with said wheels for causing the same torotate in synchronism.

3. Apparatus for making grommets as dened by claim 2 characterized bysaid frame having a hole in the end thereof adjacent said one of saidwheels in alignment with said eye.

4. In a method of making a grommet, the steps including mounting a coilof wire strand of predetermined length between a pair of spaced coaxialwheels, threading one end of the strand through a central eye in one ofthe wheels, drawing out the strand to form a loop lying laterally ofsaid wheels, threading said one end through the peripheries of the twowheels and seizing said one end into contact with the portion of thestrand issuing from said eye to form a core in the shape of a closedloop, turning said wheels and throwing the loop as a hoop around thewheels and coil at each revolution of the wheels to wind the strandissuing from said eye about said core, and continuously pulling the corein an axial direction through the wheels whereby the strand issuing fromthe eye is laid on the core in helical convolutions.

5. In a method of making a grommet as defined by claim 4 including thesteps of removing a portion of the core adjacent said one end, andinserting the other end of the strand in the space thus left vacant.

6. In a method of making a grommet, the steps including mounting a coilof wire strand between a pair of spaced coaxial wheels, said strandhaving a length necessary to form a grommet of the desiredcircumference, said strand having a helical formation except for aportion at each end thereof, one of said end portions having a lengthsubstantially equal to the circumference of the grommet to be formed,threading said last named end of the strand through a central eye in oneof the wheels, drawing out the nonhelical end portion of the strand toform a loop lying laterally of said wheels, threading said last namedend portion through the peripheries of the two wheels and seizing saidend into contact with the helically formed portion of the strand issuingfrom said eye to form a core in the shape of a closed loop, turning saidwheels and throwing the loop as a hoop around the wheels and coil ateach revolution of the wheels to wind the strand issuing from said eyeabout said core, and continuously pulling the core in an axial directionthrough the wheels whereby the strand issuing from the eye is laid onthe core in helical convolutions.

7. In a method of making a grommet as dened by claim 6 including thesteps of removing a portion of the core adjacent said iirst named end,and inserting the other end of the strand in the space thus left vacant.

References Cited in the file of this patent UNITED STATES PATENTS1,389,699 Rivett Sept. 6, 1921 1,457,691 Bull June 5, 1923 1,479,900Dorner Jan. 8, 1924 1,587,856 Reed June 8, 1926

